Fabrication of a superhydrophobic-superoleophilic particle material for oil-water separation and oil extraction

Oil-water separation has become a serious issue due to the increasing oily wastewater discharged in the environment and oil spills from time to time. Superhydrophobic and superoleophilic materials are a promising approach in oil-water separation. However, the preparation procedures for these materials are often complex and expensive, and their stability is not robust enough. In this study, superhydrophobic and superoleophilic particles are successfully prepared via a facile and green mixing method. Fluorocarbon resin, CaCO3 and SiO2 are coated on fly-ash cenospheres to form a stable superhydrophobic-superoleophilic surface, which exhibits a water and oil contact angle of 153.3 degrees and 0 degrees, respectively. To our knowledge, we're unaware of any previous study reporting a superhydrophobic-superoleophilic material prepared in such a convenient way. The as-prepared superhydrophobic material can serve as high-performance filters for separating various oil-water mixtures, with a separation efficiency up to 99.2%. And it can be applied in water-in-oil emulsion separation. Meanwhile, the asprepared particles are able to extract oils from oil-water mixtures and the oil-extraction capacity is up to 0.56 g/ g. Furthermore, the obtained material has a robust stability against various hash conditions and a good recyclability. The simply-prepared superhydrophobic cenospheres are expected to be a promising candidate for application in diverse oil-water separation situations.